Panoramic, multiplane, and transparent collimated display system

ABSTRACT

A display system for creating a multiplane display. The display system includes a viewing space for viewers. The display system includes a convex screen and a mirror element spaced apart from the convex screen to provide a collimated display. The mirror element is both reflective and transmissive of light, and a fraction of light from the convex screen that strikes a front concave surface of the mirror element is reflected into the viewing space. The convex screen and the front concave surface of the mirror element are each shaped to have an optical prescription defined for a collimated display whereby light reflected into the viewing space is collimated to provide variable depth imagery. The display system includes a background space behind the mirror element, and light from the background space from projection screens and illuminated objects is transmitted through the mirror element to viewers in the viewing space.

REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/117,196, filed on Aug. 30, 2018, which is incorporated herein in itsentirety by reference.

BACKGROUND 1. Field of the Description

The present description relates, in general, to display systems adaptedfor stereoscopic or three-dimensional (3D) image generation, and, moreparticularly, to systems and methods for producing 3D images or depthand space media illusions without requiring viewers to wear 3D glassesor other eyewear using a new collimated display design. These displaysystems may be considered multiplane or multilayer display systemsproviding a 3D display to viewers by displaying images that appear to bein two or more planes along the z-axis, and the display systems can bepanoramic in that they can be designed to provide the 3D display “in theround” such as with 3D imagery provided at 45 to 360 degrees about aviewing space (e.g., a circular room or space where a viewer would belocated when enjoying the 3D show or experience without a fixed viewingdirection).

2. Relevant Background

There is a growing demand for displays that include 3D imagery. Forexample, there is a growing trend toward using 3D projection techniquesin theatres and in-home entertainment systems including video games andcomputer-based displays. In many conventional 3D projection techniques,the right eye and the left eye images are delivered separately todisplay the same scene or images from separate perspectives so that aviewer sees a three-dimensional composite, e.g., certain characters orobjects appear nearer than the screen and other appear farther away thanthe screen. Stereoscopy, stereoscopic imaging, and 3D imaging are labelsfor any technique capable of creating the illusion of depth in an image.Often, the illusion of depth in a photograph, movie, or othertwo-dimensional image is created by presenting a slightly differentimage to each eye or the creation of parallax. In most animated 3Dprojection systems, depth perception in the brain is achieved byproviding two different images to the viewer's eyes representing twoperspectives of the same object with a minor deviation similar to theperspectives that both eyes naturally receive in binocular vision.

The images or image frames used to produce such a 3D output are oftencalled stereoscopic images or a stereoscopic image stream because the 3Deffect is due to stereoscopic perception by the viewer. A frame is asingle image at a specific point in time, and motion or animation isachieved by showing many frames per second (fps) such as 24 to 30 fps.The frames may include images or content from a live action movie filmedwith two cameras or a rendered animation that is imaged or filmed withtwo camera locations. Stereoscopic perception results from thepresentation of two horizontally offset images or frames with one ormore object slightly offset to the viewer's left and right eyes, e.g., aleft eye image stream and a right eye image stream of the same object.The amount of offset between the elements of left and right eye imagesdetermines the depth at which the elements are perceived in theresulting stereo image. An object appears to protrude toward theobserver and away from the neutral plane or screen when the position orcoordinates of the left eye image are crossed with those of the righteye image (e.g., negative parallax). In contrast, an object appears torecede or be behind the screen when the position or coordinates of theleft eye image and the right image are not crossed (e.g., a positiveparallax results).

Many techniques have been devised and developed for projectingstereoscopic images to achieve a 3D effect. One technique is to provideleft and right eye images for a single, offset two-dimensional image anddisplaying them alternately, e.g., using 3D switching or similardevices. A viewer is provided with liquid crystal shuttered spectaclesto view the left and the right eye images. The shuttered spectacles aresynchronized with the display signal to admit a corresponding image oneeye at a time. More specifically, the shutter for the right eye isopened when the right eye image is displayed and the liquid crystalshutter for the left eye is opened when the left eye image is displayed.In this way, the observer's brain merges or fuses the left and right eyeimages to create the perception of depth.

Another technique for providing stereoscopic viewing is the use ofanaglyphs. An anaglyph is an image generally consisting of twodistinctly colored, and preferably, complementary colored, images. Thetheory of anaglyph is the same as the technique described above in whichthe observer is provided separate left and right eye images, and thehorizontal offset in the images provides the illusion of depth. Theobserver views the anaglyph consisting of two images of the same objectin two different colors, such as red and blue-green, and shiftedhorizontally. The observer wearing anaglyph spectacles views the imagesthrough lenses of matching colors. In this manner, the observer sees,for example, only the blue-green tinted image with the blue-green lens,and only the red tinted image with the red lens, thus providing separateimages to each eye. The advantages of this implementation are that thecost of anaglyph spectacles is lower than that of liquid crystalshuttered spectacles and there is no need for providing an externalsignal to synchronize the anaglyph spectacles.

In other 3D projection systems, the viewer may be provided glasses withappropriate polarizing filters such that the alternating right-left eyeimages are seen with the appropriate eye based on the displayedstereoscopic images having appropriate polarization (two images aresuperimposed on a screen, such as a silver screen to preservepolarization, through orthogonal polarizing filters). Other devices havebeen produced in which the images are provided to the viewerconcurrently with a right eye image stream provided to the right eye anda left eye image stream provided to the left eye. Still other devicesproduce an auto-stereoscopic display via stereoscopic conversion from aninput color image and a disparity map, which typically is created basedon offset right and left eye images. While these display or projectionsystems may differ, each typically requires a stereographic image asinput in which a left eye image and a slightly offset right eye image ofa single scene from offset cameras or differing perspectives areprovided to create a presentation with the appearance of depth.

There is a continuous desire and need to provide new techniques thatprovide cost effective but eye-catching content with depth anddimension. For example, it is desirable to grab the attention of crowdsin shopping malls, on busy streets, in amusement parks, and othercrowded facilities such as airports and entertainment arenas, and thereis an ongoing demand to improve 3D imagery in other settings includingeducation, medicine, and gaming. As discussed above, 3D projection isone exciting way to appeal to viewers and hold their attention. However,the use of 3D projection has, in the past, been limited by a number ofissues. Typically, 3D projection is used only in low light environmentsand is not particularly effective in applications where there is asignificant amount of ambient light such as an outdoor venue during thedaytime (e.g., an amusement park or athletic stadium in the morning orafternoon where conventional 3D video image projection cannot competewith sunlight). Further, 3D projection technologies generally requirethe viewer to wear special viewing glasses, which is often inconvenientfor many applications and can significantly add to costs.

Hence, there remains a need and desire to provide new and uniquedepth-based or 3D experiences that eliminate the need for 3D glasses and3D projection technologies. Further, there is a demand to provide 3Dimagery to a viewer in more than one viewing direction so that theviewer can move about a viewing space (or at least turn their head) andbe able to perceive 3D images all about them or “in the round.”

SUMMARY

The inventors recognized that the technology behind collimated displaysmay be useful in a 3D display system to both provide 3D imagery viamultiplane images and a panoramic 3D experience, but only withsignificant modifications of conventional collimated displays to createa new collimated display assembly.

Before the inventors' work, collimated displays were used for simulationand training. The prior collimated displays incorporated opaque glassmirrors or formed metalized (i.e., opaque) polyester (e.g., a metallizedpolyethylene terephthalate (PET) film) substrates to create infinityoptics. In the cases of PET films, they are drawn down under vacuum tocreate the optical prescription used to create collimation inreflection. The metalized coating used on the PET film provides thereflector or reflective surface of the collimated display and isfunctionally opaque. In large simulation displays or simulators (e.g.,flight simulators), limiting factors in their use and design is materialsize (e.g., width) and weight. Many of these simulators are mounted tosix degree-of-freedom (6DOF) motion bases so weight is very critical.Glass mirrors are heavy, expensive to fabricate, and require seams thatare visible to the viewer. PET, vacuum-drawn, metalized mirrors orreflectors are lightweight but are typically limited to about ten feetin height and width, which limits the vertical field of view of thedisplay in some cases.

To provide a multiplane display with a collimated display assembly, thecollimated display assembly of the present description includes a mirrorelement (or reflector) that is both reflective and transmissive oflight. This is in direct contrast to the reflectors of prior collimateddisplays that were all opaque. The new collimated display assembly maybe labeled “transparent” because in proper configurations and lightingenvironments the mirror element will appear transparent to a viewerwhile it is actually being used to reflect light from a projectionscreen (or reflective display element that may, in some non-limitingexamples, take the form of a conventional front projection screen orsurface with a matte finish that defines its gain) to provide imagerythat can be designed to appear to be on nearly any plane along thez-axis relative to a viewing space and viewers in that viewing space.The projection screen (or reflective display element) and the mirrorelement's front surface have matching optical prescriptions (e.g., ashape that defines optical power) such that they work in combination (oras a collimated display assembly) to provide collimation of lightdelivered into a viewing space, which can be partially or whollysurrounded or enclosed by the front surface of the mirror element.

Because the mirror element is transmissive, a visible volumetric display(or backdrop) space can be provided in the display system behind themirror element. In one embodiment, a projection screen or wall wasprovided a predefined distance from the back surface of the mirrorelement, and a projector(s) was used to project images on thisprojection screen/wall that were concurrently visible to a viewer withthe images reflected from the mirror element's front surface but on adifferent plane (or at a different depth). The display system designcreates a physically deep, multilayer or multiplane display environmentthat enjoys the optical collimation and viewer eye point accommodationof a classic collimated display.

In one embodiment, the mirror element was provided using optically clearpolyester film, e.g., a PET film with reflectance in the range of 5 to10 percent (and with transmissivity in the corresponding range of 95 to90 percent). However, it is envisioned that the mirror element may havehigher percentages of reflectance (and, hence, less transmissivity) suchas in the range of 10 to 50 percent or the like. In contrast to flightsimulators with collimated displays, the display systems describedherein are not restricted to motion base requirements or by weight. Inthis regard, the display system may include a static, location-basedviewer environment (or viewing space) created for entertainmentapplications and other uses. Specifically, the mirror elements of thecollimated display assembly may be used to provide viewing windowsenclosing all or part of the viewing space, and these viewing windowsallow for simulation that encompasses very deep physical environmentswhen combined with projection walls/screens or other display devices inthe visible volumetric space behind the back surface of the mirrorelement(s). The clear, polyester mirror may be formed by being drawn byvacuum to the proper optical prescription such as one that matches thatof the reflective display or projection screen positioned above theviewing space (e.g., to be out of sight of viewers in the viewing space)to reflect light onto the front surface of the transparent mirrorelement.

The display system also includes a media display system such as one withone-to-many projectors provided about the periphery of the circular (orsemi-circular) projection screen (or reflective display). The mediadisplay system may be designed to provide a high resolution and a highbrightness image onto the projection screen. The image from the mediadisplay system is directed via the projection screen toward the frontsurface of the mirror element. The mirror element reflects the typicallyhigh-resolution image into the viewing space, and, in this way, themirror element acts similar to the opaque reflectors of conventionalcollimation displays. However, since the mirror element is “transparent”(e.g., is transmissive as well as reflective), the viewer is also ableto concurrently see any images displayed or physical objects in thevolumetric display space via light that is transmitted from this spacethrough the mirror element into the viewing space.

In some embodiments, the projection screen (or reflective display) isreplaced with a display element that provides the image to the frontsurface of the mirror element, and, in such embodiments, the displayelement or device may take the form of a compound organic light-emittingdiode (OLED) or liquid crystal display (LCD) flat panel or a fine pitchdirect view LED display as the imaging source. In other cases, thedisplay element can be a front or rear projected curved screen using,for example, a high definition projector. In either case, the displayelement typically will have an optical prescription corresponding withthe front surface of the mirror element so that light reflected by themirror element has proper collimation.

More particularly, a display system is provided for creating amultiplane or autostereoscopic 3D display. The display system includes aviewing space in which viewers may be positioned. The display systemalso includes a convex screen and a mirror element spaced apart from theconvex screen that may be considered a collimated display assembly. Themirror element is both reflective and transmissive of light (e.g., istransparent to translucent), and a fraction of light from the convexscreen that strikes a front concave surface of the mirror element isreflected into the viewing space. Further, the convex screen and thefront concave surface of the mirror element are each shaped to have anoptical prescription defined for a collimated display whereby thefraction of light reflected into the viewing space is collimated. Thedisplay system also includes a background space behind the mirrorelement, and light from the background space is transmitted through themirror element for concurrent viewing in the viewing space with thefraction of light reflected into the viewing space by the “transparent”mirror element.

In some embodiments, the mirror element includes a film of polyester ora sheet of formed glass. The mirror element may have a reflectance inthe range of 5 to 50 percent with some implementations using materialsproviding a reflectance in the range of 5 to 10 percent. It may beuseful in some implementation for the mirror element to be formed of afilm of optically clear polyester (e.g., Clear Mylar® or the like), andthe front concave surface is shaped (such as by drawing it down onto aframe under vacuum) to be horizontally and vertically concave to providethe optical prescription of the collimated display. To assist in propershaping, the film of optically clear polyester can be chosen to have athickness in the range of 0.5 to 2 mils.

The display system may be configured for “in the round” displays. Tothis end, the convex screen and the mirror element may both havesemi-circular or circular cross-sectional shape with coinciding centralaxes that extend in the range of 45 to 360 degrees about the centralaxes. In some cases, the convex screen is a front or rear projectionscreen, and the display system further includes a video projectorprojecting onto the convex screen to provide images in the collimatedlight directed into the viewing space. In other cases, though, theconvex screen includes a screen of a display device (e.g., an LCD, OLED,or other display device or element including, but not limited to, a finepitch LED display such as those used in large tiled arrays (e.g., aFLEXmod Adaptive LED Tile available from PixelFLEX, Tennessee, USA orthe like)) bent in two directions (e.g., horizontally and vertically) toprovide the optical prescription of the collimated display. In either ofthese cases, the light from the convex screen can be configured (e.g.,by what media is delivered to the display device or video projector) toprovide one or more images viewable by a viewer in the viewing space,and the one or more images are modified over time to appear to belocated on two or more planes along the z-axis to the viewer.

In some embodiments, the display system includes a projection wallpositioned in the background space with a front or rear projectionscreen facing a back surface of the mirror element, and light from thefront or rear projection screen is transmitted through the mirrorelement into the viewing space concurrently with the reflection of lightfrom the convex screen by the front concave surface of the mirrorelement, which furthers the depth effect or multiplane/multilayer effectof the display system. Further, in this regard, the display system mayinclude at least one physical object or character positioned in thebackground space and a light source illuminating one or more surfaces ofthe at least one physical object or character such that light from theone or more surfaces is directed through the mirror element.Additionally, the display system may include a collimated displaypositioned in the background space providing collimated light that istransmitted through the “transparent” mirror element into the viewingspace.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic or functional block diagram of a multiplane or 3Ddisplay system of the present description;

FIG. 2 is a sectional view of a large-scale implementation of a displaysystem using the collimated display technology described herein;

FIGS. 3 and 4 are top perspective views of the display system of FIG. 2;and

FIG. 5 illustrates a partial view of the display system of FIGS. 2-4from a vantage point in the entrance to the viewing space.

DETAILED DESCRIPTION

Briefly, embodiments described herein are directed towardthree-dimensional (3D) display devices or systems that areautostereoscopic, as a viewer may perceive depth or the 3D effects inthe displayed image without the use of 3D glasses or eyewear (e.g., noneed for colored or switching lenses or the like). The display systemsof the present description each include a collimated display assemblythat differs from prior collimated displays at least because it makesuse of a mirror element that is both transmissive and reflective ratherthan being opaque. The mirror element often has such low reflectancethat it may be considered “transparent” such as with reflectance below50 percent and often in the range of 5 to 15 percent. The mirror elementhas a concave reflective surface that faces a viewing space and also aprojection screen with a convex reflective surface so that it reflectslight directed from the projection screen (e.g., images from a projectoror other media source) into the viewing space and to any viewers locatedin this space.

The mirror element and the projection screen are configured with opticalprescriptions such that the reflected light from the mirror element'sconcave reflective surface is collimated light. To further the deptheffect or illusion, the display system includes a volumetricbackground/backdrop space behind the mirror element that includes one ormore background display devices (e.g., a projection wall) and/orphysical objects or set pieces illuminated by one or more light sources,and, due to the mirror element being transmissive, the viewer in theviewing space is able to observe these background displays and/orobjects concurrently with the images provided in the reflectedcollimated light. In other or the same embodiments, thisbackground/backdrop space may include or be replaced with anothercollimated display set up, either solid or reflective and transmissivelike the first layer. The mirror element may wrap around the peripheryof the viewing space along with the volumetric background space andprojection screen to provide a large range of viewing angles such as 45to 360 degrees. The media displayed on the projection screen may bevaried over time such as in size to appear to the viewer to be in aplurality of planes along the z-axis so images appear to be at differingdistances from the viewer (have varying depth). In this manner, thedisplay system is operable to provide an “in the round” multiplane ormultilayer 3D visual experience with variable depth, and, in thisregard, the use of the transparent mirror element combined with thevisible volumetric background space leads one to consider the displaysystem a variable depth Pepper's Ghost device.

The inventors recognized the significant advantage of using the opticalprescriptions and technology of collimated displays to providecollimated light to a viewer but modifying the mirror element to betransparent-to-translucent (e.g., 50 percent or less reflectance withsome embodiments using materials that are less than about 20 percentreflective such as in the range of 5 to 10 percent reflective, which maybe considered optically clear) rather than opaque (e.g., conventionalmetalized PET mirrors of collimated displays). Prior collimated displayswith opaque mirrors also had issues with segmented mirrors that includeseams that are visible. Instead, a large width (e.g., one with a widthof at least 10 feet and/or one that wraps 45 to 360 degrees about aviewing space) transparent mirror element can be provided using a singlepiece of transmissive materials such as a polyester film (such as ClearMylar®, a transparent (e.g., ultra clear transparent) PVC film (whichmay offer better flexibility when pulled under vacuum but lack some ofthe optical clarity of PET-based films such as Clear Mylar® while stillbeing inherently flame retardant), or the like). This material is formed(such as by shaping under vacuum) into a mirror element with horizontaland vertical concavity with an optical prescription corresponding with aprojection screen with a mirror surface (that is a section of ahemisphere) facing and spaced apart from the concave “front” surface ofthe mirror element. In this regard, it is often preferable to userelatively thin films such as those in the range of 0.5 to 2 mils or thelike to be shaped accurately to correct optical prescription to reflectcollimated light (as the mirror surface normalizes and magnifies lightfrom paired convex projection screen/reflective display).

FIG. 1 illustrates a 3D display system 100 that may be operated as shownto provide a multiplane, autostereoscopic display experience for aviewer 106 positioned in a viewing space 104. The system 100 includes acollimated display assembly 110 that includes a media display system 112that may include one or more devices for providing light 113 with 2D or3D imagery (but typically not stereo), and the system 112 may includeone, two, three, or more video projectors that may be chosen to be highresolution and/or high brightness (such as 8000 to 25000 or more lumenratings). The media light 113 is directed toward a projection screen 114where it strikes a reflective surface 116 that is generally convex andmay be a mirror with an optical prescription paired with that of mirrorelement 120 (e.g., a mirror shaped as a section of a hemisphere).

As shown, the mirror element 120 is a concave transparent mirror formedof a material that is both transmissive and reflective and with itsconcave reflective front surface 122 facing the convex reflectivesurface 116 of the projection screen 114. The light 117 reflected fromthe projection screen 114 is directed onto the front surface 122 where afraction (e.g., 5 to 10 percent or more) is reflected as light 123 thatis directed into the viewing space 104 and toward viewer 106. Thesurface 122 is shaped to be concave in both the vertical and horizontaldirections with an optical prescription corresponding to that of surface116 so that the light 123 is collimated light (for both the horizontaland vertical directions), which forces the viewer 106 to focus toinfinity. The distance between the surface 116 and the surface 122 (andrelative orientations) is selected to suit the size and/or opticalprescriptions of the two surfaces 116 and 122 to achieve the desiredcollimation of light 123 reflected from the front surface 122. Themirror element 120 may be formed of nearly any material with desiredpercentages of reflectance and transmissivity such as formed glass.However, some preferred embodiments of system 100 utilize an opticallyclear polyester film (such as clear PET film or the like) that is shaped(such as by drawing it under vacuum into a frame) to have its frontsurface be concave with the desired optical prescription to reflect andcollimate the received light 117 as shown at 123.

Since the mirror element 120 is also transmissive to light, a fractionof the light 117 that strikes the mirror element 120 is transmitted, asshown with arrows 125, through the element 120 and out via back surface124 to a volumetric background/backdrop space 130 behind the mirrorelement 120. Also, since the mirror element 120 is “transparent,” lightfrom the space 130 is transmitted through the mirror element 120 intothe viewing space 104 where it can be concurrently perceived by theviewer 106 with the collimated light 123 and any imagery it contains.The display system 100 includes one or more background display devices132 that display images on one or more of their surfaces, and light 133from these surfaces is transmitted from the space 130 to strike the backsurface 124 of the mirror element 120. The light 133 passes through thetransmissive material of the element 120 and then into the viewing space104 and to viewer 106. In some embodiments, the device 132 is aprojection screen/wall that is projected upon (front or rear projection)by a projector.

Images displayed upon the surfaces of the device 132 appear to theviewer 106 to be at a depth or distance, d₁ (i.e., distance betweensurfaces of device 132 and present location of viewer 106 in the space104). The imagery provided by the collimated display assembly 110 can bedesigned to appear at any plane along the z-axis between the viewer 106and the surfaces of the background display device and their location maybe varied over time so that the images appear to move toward or awayfrom the viewer 106. Additionally, the display system 100 may includeone or more physical objects or props (or set pieces) 136, and one ormore light sources 134 may be operated to illuminate surfaces of theobject 136 with light 135. Reflected light 137 from the surfaces of theobject 136 is transmitted through the transparent mirror element 120 andinto the viewing space 104 so that the viewer 106 perceives the object136 at a distance, d₂, from their current location in the viewing space.The distance, d₂, may be chosen to differ from the distance, d₁, to thedisplay device's surfaces to further enhance the depth effect of thesystem 100.

The concepts of a collimated display system that makes use of a“transparent” mirror element shown in FIG. 1 can be scaled upward to arelatively large display system that can provide viewing “in the round.”FIG. 2 illustrates a sectional view of a large version of a displaysystem 200 that may be used to provide numerous people or viewers 206 ina display space 204 a 3D viewing experience, and the viewing space 204may be a portion of a restaurant, an immersive entertainmentenvironment, or the like. As shown, the viewing space 204 is enclosed ordefined with a set of windows 206, which may be formed of nearly anyclear material such as glass, and the windows 206 are an optionalfeature of the system 200 that are used in part to keep the viewers 206from touching other system components (such as the reflective surface222 of the mirror element 220) and are not included for functionsrelated to providing a 3D display or visual experience.

As shown, the system 200 includes a video projector 210 (i.e., toprovide the functions of the media display system 112 of FIG. 1) thatoperates to project still or video imagery via projected light 211.Typically, the system 200 will include one, two, three, or moreadditional projectors 210 or display devices to provide high quality andhigh brightness lighting to all of the reflective surface 216 of aprojection screen 214. The projection screen 214 is shown to bepositioned above the center of the viewing space 204 such as with acenter axis of the space 204 (which may be circular or semi-circular inshape) coinciding with a center axis of the semi-spherically shapedprojection screen 214. In other embodiments, though, the screen 214 (andprojectors 210) may be positioned below the flooring defining the lowersurfaces of the space 204.

As described for projection screen 114 of FIG. 1, the projection screen214 provides a component of a collimated display assembly and has areflective surface 216 that is convex with a shape (e.g., asemi-hemispherical shape) having an optical prescription suited for acollimated display. The surface 216 in this embodiment extends wholly(i.e., 360 degrees) about a central axis to take on a large toroidshape. In other embodiments, though, the surface 216 may extend to asmaller amount such as in the range of 45 to 360 degrees. The use atoroid shaped reflective surface 216 allows the collimated displayassembly to generate imagery for viewing in any direction in the viewingspace 204 (e.g., a viewer 206 may have a viewing angle from 0 to 360degrees).

As another piece of the collimated assembly, the system 200 includes amirror element 220 that extends about the periphery of the viewing space204. The mirror element 220 is formed of a material that is bothreflective and transmissive of light such as a clear-to-translucentpolyester film, formed glass or plastic, and the like. The mirrorelement 220 is also generally toroidal or semi-spherical in shape andits central axis coincides with that of the projection screen 214. Themirror element 220 includes a front reflective surface 222 that isconcave in both the horizontal and vertical directions with a shapeproviding it an optical prescription that when paired with that of thereflective surface 216 of the projection screen 214 enables it to outputcollimated light.

Particularly, light 217 that is reflected from the reflective surface216 is directed onto the concave front surface 222 of the mirror element220. A fraction (e.g., 5 to 10 percent or more) of the light 217 isreflected as shown with arrow 223 into the viewing space 204 ascollimated light. As a result, the viewers 206 can perceive images 224in a plane at nearly any point (any depth) along the z-axis. In thisexample, the images 224 are shown to appear to be located between thewindow 206 and the front surface 222 of the mirror element 220, but theymay also be generated (via media supplied to projector 210) to appear atsome distance behind a back surface 226 of the mirror element 220.

In contrast to conventional Pepper's Ghost displays, the depth at whichthe images 224 appear to be located is not static or limited by alocation of the projection screen 214, but, instead, the images 224 areprovided by collimated light 223 so that they can have variable depth ora depth that can be changed over time. The mirror element 220 may bequite large without seams (or with minimal seams) such as with a heightin the range of 6 to 10 feet or more and with a diameter of 10 to 50feet or more. To facilitate fabrication of such a large mirror element220, it may be useful to fabricate it from an optically clear (ortranslucent in some cases) polyester film (e.g., Clear Mylar® or Type AMylar® or the like), and the shape with the optical prescription forcollimation of light 206 may be created by drawing it down onto framingelements under vacuum. As with the projection screen 214, the mirrorelement 220 may extend wholly or some fraction of a circumference toenclose the viewing space 204 such as 45 to 180 degrees (as shown inFIG. 2) up to 360 degrees.

To further the depth effect, the display system 200 includes avolumetric background/backdrop space 230 behind the back surface 226 ofthe mirror element. The volumetric background space 230 is visible tothe viewers 206 in the viewing space 204 under proper lightingconditions through the mirror element 220, which is at least translucentto light and more typically optically clear. As shown, a projection wall232 is provided in the space 230 a distance (e.g., 2 to 20 feet or more)from the back surface 226 of the mirror element 220. The projection wall232 may be belt or hoop shaped as shown and extend about the entirelength or circumference of the mirror element 220 or some fraction ofthis length/circumference. One projection wall 232 may be used as shownor two, three, or more projection walls 232 may be used as desired. Thedisplay system 200 may also include one or more physical objects (props,set pieces, characters/actors (human or robotic), and the like)positioned between the mirror element 220 and the projection wall 232(which is opaque in many cases).

The projection wall 232 may be provided via a front or rear projectionscreen in some cases along with one or more video projectors (not shownin FIG. 2). Light reflected or transmitted from the front surface 234 ofthe wall 232 passes through the mirror element 220 so that the viewers206 in the viewing space 204 can view images 235 that have depth as theyappear at the location of the surface 234. The images 235 areconcurrently visible to the viewers 206 with the images 224 provided bycollimated light 206 to enhance the depth effect provided by either ofthe images 224, 235 (e.g., the images 235 appear to be further away fromthe viewers 206 than the images 224). Special effects can be achieved bybalancing the lighting levels on both sides of the mirror element 220and/or by carefully choosing and/or generating the images 224, 235(e.g., only use brighter colors for image 224 and keeping space 230relatively dark to avoid washing out the reflected images 224 fromsurface 222).

FIGS. 3 and 4 illustrate the display system 200 from a top perspectiveview. As shown, an entrance or entry/exit space 360 is provided in thedisplay system 200. This is achieved by extending the projection wall232 and the mirror element 220 some amount less than 360 degrees aboutthe central axis of the three components projection screen 214, mirrorelement 220, and projection wall 232 (labeled 302 in FIG. 3). Forexample, the projection wall 232 and the mirror element 220 may extendin the range of 315 to 345 degrees about the central axis 302 to provideentrance 360 with hole/gap 362 in the wall 232, hole/gap 364 in themirror element 220, and a gap/recessed portion 366 in the reflectivesurface 216 of the projection screen 214 of the collimated displayassembly. Structural walls 368 may connect these holes/gaps 362 and 364define a hallway into and out of the viewing space 204 for viewers (notshown in FIGS. 3 and 4).

The design of display system 200 provides a nearly complete theater “inthe round” experience as the viewers in space 204 can change theirhorizontal viewing angles or POVs in nearly a full circle and stillconcurrently observe images via the reflected collimated light from thesurfaces 222 and via light transmitted or reflected from the innersurface 234 of the projection wall 232 that pass through thetransparent-to-translucent mirror element 220. Other designs may providea full 360-degree experience (or provide one with a smaller extensionthan shown such as in the range of 45 to 180 degrees or the like aboutthe central axis 302).

Each component 214, 220, and 232 is a concentric shape (a toroidalshape, semi-cylindrical or belt shape, or semi-spherical shape) aboutthe central axis 302. To achieve a desired normalization andmagnification (or collimation) of light from the projection screen 214,the mirror element's front or inner surface 222 is spaced apart from thereflective surface 216 of the projection screen 214 a predefineddistance, d₃, such as 3 to 15 feet or more in this large-scaleimplementation of the display system 200.

To provide further depth to the display system 200, the inner or frontsurface 234 of the projection wall 232 is spaced apart the distance, d₁,from the back surface 226 of the mirror element 220. The spacing definesthe size of the visible volumetric background space 230 in whichadditional display devices and/or physical objects (e.g., set pieces orprops or characters) may be positioned and illuminated for viewing byviewers in the centrally-located viewing space 204. This distance, d₁,may be constant or may be varied to achieve desired depth and/or displayeffects in the display system 200. The projection wall 232 has a heightthat typically is at the same or greater than a height of the mirrorelement 220 so that viewers can see imagery displayed on surface 234regardless of their vertical viewing angle or POV. The projection wallmay be achieved with front or rear projection techniques, but someembodiments of the display system 200 may provide the projection wall232 using an additional collimated display assembly included in thedisplay system 200 (not shown but understood through the discussion ofFIG. 1 and components 210, 214, and 220 of FIGS. 2 and 3).

In FIG. 2, the projection screen 214 was illustrated as using frontprojection to provide media via a reflective surface with a particularoptical prescription to provide collimation of light when combined withconvex surface 222 of the mirror element 220. More generally, theprojection screen 214 may be a media display with an opticallyprescriptive screen for use in a collimated display. With this in mind,the projection screen 214 may also be configured as a rear projectionscreen and the projector(s) 210 of FIG. 2 may be positioned to projectlight onto a back or rear surface of the surface 216 (which would nothave to be a reflective surface but would instead transmit light ontothe front surface 222 of the mirror element 220). In still otherembodiments of the display system 200, the media display 214 includesone or more display devices or tiles to provide the screen 216 with anoptical prescription suited to the surface 222 to provide images viacollimated light. For example, the media display 214 may include one ormore LEDs, OLEDs, or the like with display screens that are bent into ashape (e.g., into vertical and horizontal curves) to provide the screen216 with the required optical prescription.

FIG. 5 illustrates a partial view of the display system of FIGS. 2-4from a vantage point to show the viewing space 204, e.g., from alocation in the entrance 360. As shown, a viewer 206 is located withinthe viewing space underneath the projection screen/media display 214.During operations of the display system 200, media is displayed upon orreflected off the screen 216, which is convex with a first part of anoptical prescription for a collimated display. Light from the screen 216is directed onto spaced-apart but adjacent front concave surface 222 ofthe mirror element 220, and this light is partially reflected andpartially transmitted. Hence, a fraction of the light from the screen216 is reflected to the viewer 206 in the viewing space 204 via theclear windows 206. The surface 222 is shaped to provide the second partof the optical prescription for the collimated display such that thefraction of light that is reflected is collimated light, and imageryprovided by this collimated light may be configured or designed toappear at nearly any distance from the viewer 206 (or from locationswithin the viewing space) from several feet up to infinity. Although notshown in FIG. 5, the viewer 206 also is able to concurrently perceiveany illuminated objects or screens and/or light from displays in thebackground space behind the “transparent” mirror element 220.

Although the invention has been described and illustrated with a certaindegree of particularity, it is understood that the present disclosurehas been made only by way of example, and that numerous changes in thecombination and arrangement of parts can be resorted to by those skilledin the art without departing from the spirit and scope of the invention,as hereinafter claimed.

The transparent collimation display assembly of the systems taughtherein may use lightweight, low-cost polyester membranes to create the3D illusion. The optically clear polyester material can be purchased invery large web widths (e.g., 25 to 100 feet or more) while metalizedpolyester is presently only available up to ten feet wide. Theavailability of wide width clear polyester unlocks the ability to createextremely large collimated environments—as the clear reflector can bewrapped around all or parts of a relatively large viewing space—that aresuited to large scale attractions, restaurants, and special eventvenues. In addition, this clear material for the reflector of thecollimated display assembly is available in Underwriters' Laboratories(UL) certified flame-retardant formulations (VTM-0 class UL 94 flameretardant), which may be very desirable for use in many entertainmentand other facilities.

An additional advantage of thin polyester films (non-metallized) is thatthe material is so thin (e.g., 0.5 to 1 mil for transparent standardgrade PET film and up to 0.5 to 10 mils for optically clear polyesterPET or the like) that it eliminates double reflection due to materialthickness. This thin material can be drawn down with a vacuum orpressurized with positive pressure to create the optical prescriptionrequired to provide collimation of reflected light. This compoundshape—the front surface of the reflector or mirror element ishorizontally and vertically concave—can be accurately maintained at theproper shape using sensors and controls that constantly monitor theshape and depth of the material.

The display systems are also unique in their ability to create a trulyimmersive environment using collimated optics at a huge scale. A keyfeature in this regard is the use of the clear material as the primaryreflector or mirror element of the collimated display assembly. Bycontrolling the shape of its front surface (surface facing the viewingspace), the benefit of collimation is obtained in combination with thephysical depth of a classic Pepper's Ghost illusion so that the displaysystem may be thought of as a variable depth Pepper's Ghost system (asthe reflected image can be generated by the media display system toappear at nearly any depth or at any plane along the z-axis). Unlike aconventional Pepper's Ghost system, the technique described hereinforces the human eye to accommodate at infinity. This depth cue causesthe brain to accept the reflected imagery at infinity so that theperception of the environment can be controlled. For example, an outerspace environment will no longer look like a two-dimensional (2D)display representing an infinite environment.

Included in this advantage is that the physical environment behind thecollimation optics (often labeled the visible volumetric display (orbackdrop or background) space or assembly) can be physically augmentedwith scenery and/or projection surfaces (or other display devices) thatcan be coordinated spatially with digital 2D or 3D rendered media (notstereo so no eyewear required). This includes interactive elements suchas laser blasts or similar visual special effects that appear to emanatefrom the viewer's point of view (POV) and into the environment, which isa unique feature previously only available using stereo techniques thatutilized glasses or head-mounted VR/AR hardware.

In the theme park setting, one can foresee a ride system that passesalong a viewing path that incorporates the display system in long linearpaths allowing the rider to look at infinity with foreground real-timegenerated content that is interactive. In other settings, a restaurantcan provide tables in the viewing space to provide a 360-degree view ofouter space with foreground space ships and planets while the galaxiesin the background are perceived at infinity. In another example, anunderwater experience may be provided that looks and is perceived to beinfinitely deep with fish creating a truly digital aquarium. Further, atheatrical experience can be provided with a theater designed toaccommodate the display system and its display techniques in a widefield of view for the audience.

We claim:
 1. A display system for providing a multiplane display in aviewing space, comprising: a convex screen; a mirror element spacedapart from the convex screen, wherein the mirror element is reflectiveand transmissive of light, wherein a fraction of light from the convexscreen that strikes a front concave surface of the mirror element isreflected into the viewing space, and wherein the convex screen and thefront concave surface of the mirror element are each shaped to have anoptical prescription defined for a collimated display whereby thefraction of light reflected into the viewing space is collimated.
 2. Thedisplay system of claim 1, wherein the mirror element comprises a filmof polyester or a sheet of formed glass or plastic.
 3. The displaysystem of claim 1, wherein the mirror element has a reflectance suchthat the fraction is in the range of 5 to 50 percent.
 4. The displaysystem of claim 3, wherein the mirror element is configured such thatthe fraction is the range of 5 to 10 percent.
 5. The display system ofclaim 1, wherein the mirror element is formed of a film of opticallyclear polyester with a thickness in the range of 0.5 to 2 mils.
 6. Thedisplay system of claim 1, wherein the front concave surface is shapedto be horizontally and vertically concave to provide the opticalprescription of the collimated display.
 7. The display system of claim1, wherein the convex screen and the mirror element have semi-circularor circular cross-sectional shapes with coinciding central axes andextend in the range of 45 to 360 degrees about the central axes.
 8. Thedisplay system of claim 1, wherein the convex screen comprises a frontor rear projection screen and the display system further includes avideo projector projecting onto the convex screen to provide images inthe collimated light directed into the viewing space.
 9. The displaysystem of claim 1, wherein the convex screen includes a screen of adisplay device bent in two directions to provide the opticalprescription of the collimated display.
 10. The display system of claim1, wherein the light from the convex screen is configured to provide oneor more images viewable by a viewer in the viewing space and wherein theone or more images are modified over time to appear to be located on twoor more planes along the z-axis to the viewer.
 11. The display system ofclaim 1, further comprising a collimated display providing collimatedlight that is transmitted through the mirror element into the viewingspace.
 12. A display system for providing a multiplane display,comprising: a media display with a convex screen; and a mirror elementwith a concave front surface facing the convex screen, wherein themirror element is reflective and transmissive of light, wherein afraction of light from the convex screen that strikes the front concavesurface of the mirror element is reflected, wherein the convex screenand the front concave surface of the mirror element have an opticalprescription defined for the collimated display whereby the fraction oflight reflected is collimated, and wherein the front concave surface ofthe mirror element is shaped to be horizontally and vertically concaveto provide the optical prescription of the collimated display.
 13. Thedisplay system of claim 12, wherein the mirror element comprises a filmof polyester or a sheet of formed glass or plastic and wherein thefraction is less than 20 percent, whereby the mirror element issubstantially transparent.
 14. The display system of claim 12, whereinthe mirror element is formed of a film of optically clear polyester. 15.The display system of claim 12, wherein the convex screen and the mirrorelement have semi-circular or circular cross-sectional shapes withcoinciding central axes and extend in the range of 45 to 360 degreesabout the central axes.
 16. The display system of claim 12, wherein theconvex screen comprises a front or rear projection screen and thedisplay system further includes a video projector projecting onto theconvex screen to provide images in the collimated light directed intothe viewing space.
 17. A display system for providing a multiplanedisplay in a viewing space, comprising: a mirror element with a concavefront surface that is reflective and transmissive of light, wherein theconcave front surface reflects collimated light during operations of thecollimated display assembly into the viewing space and wherein lighttransmitted through the mirror element into the viewing space isviewable in the viewing space concurrently with the reflection of thecollimated light by the concave front surface of the mirror element; anda media display with a convex screen providing imagery via light outputonto the front concave surface of the mirror element, wherein the convexscreen and the front concave surface have corresponding opticalprescriptions to produce the collimated light, and wherein the mirrorelement is configured such that a fraction of the light output onto thefront concave surface in the range of 5 to 50 percent is reflected bythe front concave surface.
 18. The display system of claim 17, whereinthe mirror element is formed of a film of optically clear polyester. 19.The display system of claim 17, wherein the front concave surface isshaped to be horizontally and vertically concave to provide an opticalprescription of the collimated display assembly to provide thecollimated light.
 20. The display system of claim 17, wherein the mirrorelement has a semi-circular or circular cross-sectional shape andextends in the range of 45 to 360 degrees about a central axis.